Gain of 1q confers an MDM4-driven growth advantage to undifferentiated and differentiating hESC while altering their differentiation capacity

Abstract

Gains of 1q are a highly recurrent chromosomal abnormality in human pluripotent stem cells. In this work, we show that gains of 1q impact the differentiation capacity to derivates of the three germ layers, leading to miss-specification to cranial placode and non-neural ectoderm during neuroectoderm differentiation and by poorer expression of lineage specific markers in hepatoblasts and cardiac progenitors. Competition assays show that the cells retain their selective advantage during differentiation, which is mediated by a higher expression of MDM4, a gene located in the common region of gain. MDM4 drives the winner phenotype of the mutant cells in both the undifferentiated and differentiating state by reducing the cells sensitivity to DNA-damage through decreased p53-mediated apoptosis. Finally, we find that cell density in culture plays a key role in promoting the competitive advantage of the cells by increasing DNA damage.

Aberrant Wnt activation in recurrent genetically variant human pluripotent stem cells impairs cardiomyocyte differentiation and phenotype

“…Specifically, we noted an increase in prevalence of chromosome 1q gains in recent years, associated with increased use of feeder-free cultures 15 . Our work 15 and that of others 16 , showed that MDM4 is a likely driver gene for the selective advantage of variant 1q cells, allowing variants to rapidly take over cultures through faster proliferation and reduced apoptosis. Given the prevalence of chromosome 1q variants in hPSC culture in recent years, a question arises whether the gains of chromosome 1q affect downstream application of hPSCs, such as their use for generating differentiated cells?…”

Gain of chromosome region 1q31.3 in human iPSCs confers growth advantage and alters contraction in derivative cardiomyocytes

“…Recent studies have reported that the anti-apoptotic gene MDM4, located in the duplicated chromosomal region, as the likely driver for the competitive advantage of hPSCs containing a gain of chromosome 1q (Krivec et al, 2023;Stavish et al, 2023).…”

“…Aberrations in chromosome 1q are recurrent in hPSCs, with the prevalence of this abnormality increasing in recent years and correlating with a shift from the culturing of hPSCs on mouse embryonic fibroblasts (Stavish et al, 2023). Recent studies have reported that the anti-apoptotic gene MDM4, located in the duplicated chromosomal region, as the likely driver for the competitive advantage of hPSCs containing a gain of chromosome 1q (Krivec et al, 2023; Stavish et al, 2023). MDM4 suppresses the p53 response to cellular stress, thereby increasing the threshold for triggering apoptosis.…”

“…Notably, chromosomes 1, 12, 17, 20 and X are particularly prone to full or partial gains in hPSCs (Baker et al, 2016; Draper et al, 2004; The International Stem Cell Initiative, 2011; Mayshar et al, 2010; Taapken et al, 2011). These aberrations often confer a growth advantage for the variant hPSCs, resulting in these cells eventually outcompeting the wildtype hPSC population in culture (Krivec et al, 2023; Nguyen et al, 2014; Stavish et al, 2023). However, at early cell passages it is often possible to find a mosaic population of variant and normal cells (Baker et al, 2007).…”